Related papers: Dynamics in near-threshold $J/\psi$ photoproductio…
Bound-state corrections to $J/\psi$ production from almost real photons are calculated in the colour-singlet model. A systematic, gauge-invariant, theory of hard quarkonium processes is used upto $O(v^2)$, where $v$ is the relative velocity…
It has been suggested that the production of a heavy quarkonium near threshold in electron-proton scattering can shed light on the origin of the proton mass via the QCD trace anomaly. We study the photoproduction of $J/\psi$ off the proton…
Background: A nonperturbative charm production contribution, known as intrinsic charm, has long been speculated but has never been satisfactorily proven. The SeaQuest experiment at FNAL is in an ideal kinematic region to provide evidence of…
Using short distance QCD methods based on the operator product expansion, we calculate the $J/\psi$ photoproduction cross section in terms of the gluon distribution function of the nucleon. Comparing the result with data, we show that…
We consider J/psi meson photoproduction on protons at high energies at the leading order in alpha_s using conventional parton model and k_t-factorization approach of QCD. It is shown that in the both cases the colour singlet mechanism gives…
Perturbative QCD is applied to investigate the near threshold heavy quarkonium photoproduction at large momentum transfer. We take into account the contributions from the leading three-quark Fock states of the nucleon. The dominant…
We investigate $J/\psi$ photoproduction off the nucleon using a dynamical model based on a Hamiltonian framework. First, Pomeron exchange is regarded as a background contribution that accounts for the gradual rise of the total cross section…
Based on the vector meson dominance assumption, a Hamiltonian model has been developed to investigate $J/\Psi$ photo-production reaction on the nucleon by using the $J/\Psi$-nucleon potential extracted from a lattice QCD calculation of…
We investigate the proposal that the rise with energy of the ratio of the exclusive photo-production cross-sections of vector mesons $\Psi(2s)$ and $J/\Psi$ can serve as an indicator for the presence of high gluon densities and associated…
We study J/psi photoproduction via the fusion and fragmentation mechanisms at the HERA Collider within the frameworks of the collinear parton model and the quasi-multi-Regge kinematics approach using the factorization formalism of…
The electroproduction of J/psi and psi(2S) mesons is studied in elastic, quasi-elastic and inclusive reactions for four momentum transfers 2 < Q^2 < 80 GeV^2 and photon-proton centre of mass energies 25 < W < 180 GeV. The data were taken…
We compute the charm dijet photoproduction cross section at next-to-leading order of QCD in the zero-mass variable flavour number scheme, i.e. with active charm quarks in the proton and photon. The results are compared to recent…
We discuss the production of $D$ mesons and $J/\psi$ quarkonia in proton-nucleus collisions in the fixed-target LHCb experiment. We consider gluon-gluon fusion within $k_t$-factorization, processes initiated by intrinsic charm in the…
We construct a framework for near-threshold $J/\psi$ photoproduction that combines a target-mass-corrected gluon-PDF moment expansion with an explicit scalar gravitational form factor associated with the QCD trace anomaly. Both…
We report on our recent calculation of the inclusive direct photo- and hadroproduction of the J/psi meson at next-to-leading order within the factorization formalism of nonrelativistic QCD. We fit the color-octet (CO) long-distance matrix…
The $J/\psi$ production originating from elastic and inelastic photoproduction processes in p-p collisions at LHC energies is investigated, where the fragmentation processes are involved. An exact treatment is performed, which adopts the…
The recent precise experimental results for the photoproduction of $\eta$-mesons off the neutron measured with the Crystal Ball/TAPS calorimeter at the MAMI accelerator have been investigated in detail in the framework of the Bonn-Gatchina…
Recent DESY-HERA data on $J/\Psi$ elasticity distribution show that it emerges mostly as a fast particle. Interpreting photoproduction as a collision between a pre-formed charmed hadron and the proton, the outcoming $J/\Psi$ is a leading…
We study the polar and azimuthal decay angular distributions of $J/\psi$ mesons produced in semi-inclusive, deep-inelastic electron-proton scattering. For the description of the quarkonium formation mechanism, we adopt the framework of…
Inelastic and diffractive production of J/psi mesons at HERA is reviewed. The data on inelastic photoproduction are described well within errors by the Colour Singlet Model in next-to-leading order. A search for colour octet processes…